Acoustic transformer



Oct. 8, 1929. P. A. ROBBINS v1,730,530

jACOUSTI C TRANSFORMER aFiled Nov. 30, 1928 Patented Oct. 8, 1929PATENT; OFFICE PERCY A. ROBBINS, OF HIGHLAND PARK, ILLINOIS ACOUSTICTRANSFORMER Application filed November 30, 128. Serial No. 322,897.

This invention relates to improvements in certain apparatus for which apatent was granted to me June 5, 1928, the number of the said patentbeing 1,67 2,47 2.

5 In the above patent I showed an acoustic transformer which consists ofan expansion chamber through which a stream of dense gaseous medium iscaused to flow and expand as it flows, the said gaseous medium passingin contact with a small vibrating diaphragm from which sound waves areemitted, the said sound waves being propagated along the flowi'ng streamof gaseous medium to a second diaphragm larger than the first and thegaseous medium being returned through a closed cir cuit to a compressorand then back to the said ex ansion chamber.

n my previous'invention the gaseous medium when entering the expansionchamber may be wet with a mist of particles condensed from the gaseousmedium. My present invention relates to a means for expanding someliquid such as water or mercury into a gas, charging the said gas with amist of condensation, expanding the mist and the particles ofcondensation, condensing the expanded gas back into its liquid form,such as water or mercury, and returning the condensed liquid back to thepoint where it will again be expanded into a gaseous condition andreturned to the expansion chamber all in a closed cycle. In theaccompanying drawing which is a diagrammatical vertical section, 1 is aboiler with flues 2 through which pass hot' gases from the heater 3. Anykind of a heater will do but I show a gas burner controlled by a valve4. Liquid surrounds the tines and is boiled into a gas or vapor whichdischargesthrough the orifice 5 to the throat 6 of the expansion chamber12. An electric heater 11 may be used for evaporating the liquid insteadof the gas heated boiler, the heat being supplied by the electricresistance coil 11.

The throat 6 of the expansion chamber is provided with the annularcooling ring 7 through which flows a stream of water regulated by thevalve 8. An electrically vibrated diaphragm 13 imparts vibrations to thegas in the chamber 12 and these vibrations are propagated to the largeclosing diaphragm 14 closing the end of the chamber 12 The vapor fromthe chamber 12 passes out through the orifice l5 and is conveyed by apipe to the condenser 16. Any condensate which may form in the chamber12 is drained away through the pipe 17 to the condenser 16.

The condenser 16 is of ordinary type in its design. Cooling water flowsthrough the pipe 18 and tubes 20, 20 to the outlet 19-. Gas from theexpansion chamber enters the top of the condenser and dischar es whencondensed to liquid form throng the pipe 21. The condensed liquid flowsthrough the nonreturn valve 22 to the boiler 1 thus completing theclosed circuit.

While I have shown the use of a water cooled condenser and a watercooled throat to the expansion chamber, I also contemplate the use ofair cooling devices from which the heat is radiated by the use of metalfins or webs as is common practice in other arts.

In the operation of apparatus of this type there is likely to occur acollection of dry gas such as air which cannot be condensed to a liquidby the meansemployed, and in order to 7 get rid of this gas I providethe valve .23 through which such gas may be discharged. When theapparatus is allowed to cool a vacuum would tend to form which might beundesirable, but by means of the valve 23 such a vacuum may bedestroyed.

What I claim as my invention is:

1. The method of imparting vibrations from a vibratable diaphragm to theatmosphere or vice versa which consists in employing as the transferringmedium a stream of a condensable gaseous medium contacting with thediaphragm and moving in a closed circuit, and in creating andcirculating said gaseous medium by continuously vaporizing andcondensing a vaporizable liquid.

2. The method of imparting vibrations from a vibratable diaphragm to theatmosphere or vice' versa which consists in employingas the transferringmedium a stream of a condensable gaseous medium contacting with thediaphragm and moving in a closed circuit over and past a second andlarger diaphragm, and in creating and circulating said gaseous medium bycontinuously vaporizing and condensing a vaporizable liquid.

3. The method of imparting vibrations from a vibratable diaphragm to theatmosphere or vice versa which consists in employing as the transferringmedium a stream of a condensable gaseous medium contacting with thediaphragm and moving in a closed 7 circuit, creating and circulatingsaid gaseous medium by continuously vaporizing and condensing avaporizable liquid and in effecting a slight cooling of the gaseousmedium before 'it passes over the first diaphragm to form a mist ofcondensed particles in said medium.

4. An acoustic transformer comprising an expansion chamber; a vibratablediaphragm fitted in said chamber; a second diaphragm closing an openingin said chamber; a circuit for fluids communicating at opposite. endswith the chamber adjacent the diaphragms; means included in the circuitadapted to vaporize a liquid; and a condenser between the vaporizingmeans and the end of the circuit adjacent the second diaphragm, wherebythe vapor flowing through the expansion chamber is condensed for re-use.

5. An acoustic transformer comprising an expansion chamber; a vibratablediaphragm fitted in said chamber; a second diaphragm closing an openingin said chamber; a circuit for fluids communicating at opposite endswith the chamber adjacent the diaphragms; means included in the circuitadapted to vaporize a liquid; a condenser between the vaporizing meansand the end of the circuit adjacent the second diaphragm, whereby thevapor flowing through the expansion chamher is condensed for re-use; anda check valve in the circuit preventing back flow of liquid from thevaporizer to the condenser.

6. An acoustic transformer comprising an expansion chamber; a vibratablediaphragm fitted in said chamber; a second diaphragm closing an openingin said chamber; a circuit for fluids communicating at opposite endswith the chamber adjacent the diaphragms; means included in the circuitadapted to vaporize a liquid a condenser between the vaporizing meansand the end of the circuit adjacent the second diaphragm, whereby thevapor flowing through the expansion chamber is condensed for re-use; anda valve controlled opening into said chamber whereby any vacuum thereinmay be broken or-non-condensable gases vented.

7'. An acoustic transformer comprising an expansion chamber; avibratable diaphragm fitted in said chamber; a second diaphragm closingan opening in said chamber; a circuit for fluids communicating atopposite ends with the chamber adjacent the diaphragms; means includedin the circuit adapted to vaporize a liquid; a condenser between thevaporizing means and the end of the circult ad acent the seconddiaphragm,

